I see a bunch of transactional send journeys and I was wondering where the event defintion key comes from?
In Journey Builder under events - entry sources I can create an event and get the event defintion key which I can then plug into the event defintion in The transactional journey send - right?
But my current transactional journey's have event defintion keys that I cannot find at all in entry sources. IS there another place in Marketing Cloud that generates event definition keys? Or alternatively is it possible that maybe an external source gave us the key?